[Q fever : A rare differential diagnosis of granulomatous disease]. / Q-Fieber : Eine seltene Differenzialdiagnose granulomatöser Erkrankungen.

Q fever is a worldwide distributed zoonotic disease with a mostly benign course, which regularly reoccurs in Germany. This report is about a patient with sporadic serologically proven Q fever, which also showed typical histopathological findings with nonspecific granulomatous hepatitis, usually seen in acute disease. The bone marrow biopsy revealed so-called doughnut granulomas, which are not pathognomonic but a typical finding in Q fever. This case report impressively underlines that the histomorphological findings can make a decisive contribution to the clarification by extended differential diagnostics, even though it plays a subordinate role in the routine diagnostics of disseminated Q fever.

[3-Tesla MRI of rare large cystic prostate carcinoma]. / 3-Tesla-MRT von seltenen zystisch imponierenden Prostatakarzinomen.

Magnetic resonance imaging of rare cystic prostate cancers using multiparametric MRI (mp-MRI, 3 Tesla) shows, especially in solid tumor masses, the criteria of ESUR-MR classification with a PI-RADS >3 ("probably malignant"). In association with additional morphological evidence of intracystic hemorrhage and evidence of villous tumor nodules and irregular septa on the cyst wall, further malignancy criteria are met. MRI complementary to TRUS may be useful for targeted biopsy in solid tumor areas.

Oral eosinophilic ulcer, an Epstein-Barr virus-associated CD30+ lymphoproliferation?

Eosinophilic ulcer of the oral mucosa is a benign lesion of unclear pathogenesis mostly affecting the tongue. It has been suggested to represent a reactive pattern to several stimuli. We report on a 12-year-old boy who presented with a painless infiltrating ulcer on the gingiva of the lower jaw, which was covered by necrotic yellowish slough. There were no pathologic features of the jawbones or regional lymph nodes. Histopathological, immunohistochemical and gene rearrangement studies were in agreement with eosinophilic ulcer with predominant oligoclonal CD3+ and CD30+ T lymphocytes expressing the Epstein-Barr virus membrane protein. The ulcer resolved within 4 weeks and follow-up for 3 years revealed no evidence of recurrence. Epstein-Barr virus may have played a role in triggering this reactive lymphoproliferative disorder.

Synthesis and self-assembly of a functional monoclonal antibody in transgenic Nicotiana tabacum.

Immunoglobulin light and heavy chains are synthesized in mammalian cells as precursors containing a signal peptide. Processing and assembling result in formation of active antibodies. Chimeric genes have been made containing the coding sequence of the barley alpha-amylase signal peptide which has been fused to cDNAs coding for either the mature light or the mature heavy chain of a monoclonal antibody. A plasmid was constructed linking both chimeric genes under the control of plant active promoters in an expression cassette. This DNA fragment was stably integrated into the genome of Nicotiana tabacum by Agrobacterium tumefaciens mediated gene transfer. Synthesis of light and heavy chains and assembly to antibodies was detected in transgenic tobacco tissue using specific secondary antibodies. By electron microscopic immunogold labeling, the presence of assembled antibody could be detected within the endoplasmic reticulum. Affinity chromatography indicated biological activity of the assembled immunoglobulin produced in plant cells. Unexpectedly, a significant amount of assembled antibodies was found within chloroplasts.

Combined application of low temperature preparation and electron microscopic autoradiography for the localization of systemic fungicides.

The intracellular localization of the sterol-biosynthesis-inhibiting (SBI) fungicide (3H)triadimenol A is investigated in vitro in the fungus Ustilago avenae. For this purpose low temperature preparation techniques (shock freezing, freeze substitution, embedding in Lowicryl HM20) are combined with conventional electron microscopic (EM) autoradiography. In particular the suitability of Lowicryl HM20 embedded specimens for EM autoradiography with regard to the finestructure preservation is shown. For the localization of (3H)triadimenol the filamentous grain development as well as the application of the gold latensification method resulting in the appearance of spherical silver grains is tested. Fungicide sensitive wild type sporidia of U. avenae are compared with fungicide resistant cells of the mutant r8. A quantitative analysis of the autoradiographs of the wild type developed according to the gold latensification process shows a relatively homogeneous distribution of silver grains over the entire cell. On the other hand, the resistant mutant is characterized by an accumulation of silver deposits over the vacuoles as compared with the lower density of grains over the cell walls and cytoplasm. The data are discussed in the context of possible resistance mechanisms against SBI-fungicides.

A simple physical model for fungicide induced hexagonal clustering of intramembrane particles in the plasmalemma of Ustilago avenae.

Freeze fracture electron microscopy is used to study the influence of fungicide (triadimenol) treatment on the plasmalemma of sporidia of Ustilago avenae. The intramembrane particles (IMPs) randomly distributed in untreated samples form large hexagonal clusters after triadimenol treatment. A simple physical model based on length mismatch between lipid bilayer and IMPs is used to describe the interaction between the IMPs in terms of a lipid mediated potential. Using for a rough estimation also data on artificial membranes the fungicide induced ordering effect of the IMPs is discussed. A homogeneous change of lipid bilayer parameters due to the fungicide action is considered as well as a fluid-gel phase transition of the lipid matrix, which might be related to the cluster formation. Further implications of the different possibilities with respect to the mode of action of the fungicide are suggested.